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Finding the Fourth Proportional to 847.38, 1,260.12 and 821.40

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Solution

The fourth proportional to 847.38, 1,260.12 and 821.40 is: 1,221.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    847.38 : 1,260.12 = 821.40 : x
  2. Step 2: Convert to fraction form
    847.38/1,260.12 = 821.40/x
  3. Step 3: Cross multiply
    847.38x = 1,260.12 × 821.40
  4. Step 4: Simplify right side
    847.38x = 1,035,062.57
  5. Step 5: Solve for x
    x = 1,035,062.57/847.38
  6. Step 6: Final answer
    x = 1,221.49

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.